Field of the Invention
The present invention relates to a polishing liquid used for polishing a SiC substrate, and to a method of polishing a SiC substrate by use of the polishing liquid.
Description of the Related Art
In power electronics apparatuses such as inverters, there are incorporated semiconductor devices called power devices which are suitable for control of electric power. Conventional power devices have been produced mainly by using single crystal Si (silicon), and enhancement of their performance has been realized by improvements in device structure.
In recent years, however, the enhancement of device performance through improvements in device structure has been hitting a ceiling. For this reason, an attention has come to be paid to single crystal SiC (silicon carbide) which is advantageous over single crystal Si for realization of power devices with higher withstand voltage and lower loss.
Prior to fabrication of power devices into a substrate composed of single crystal SiC, a surface of the substrate is planarized by chemical mechanical polishing (CMP). In order to enhance polishing efficiency in CMP, there has been developed a polishing technique according to the use of a polishing pad containing abrasive grains and a polishing liquid having an oxidizing ability (see, for example, Japanese Patent Laid-Open No. 2008-68390).